Waterproof abrasive fabric and method of making the same



Patented Sept. 20,1927.

. nnate UNITED STATES PA'I'EN'I OFFICE. I

FRANK JOSEPH CRUPI, OF BROOKLYN, NEW YORK, ASSIGNOR'TO HERMAN BEI-IR & 00.,

INC., BROOKLYN, YORK, A CORPORATION OF NEW YORK.

WATERPROOF ABRASIVE FABRIC AND METHOD OF MAKING THE SAME.

lTo Drawing.

.tinguished from oils, varnishes or resins.

The cellulosic material is soluble in a variety v of easily vaporizable solvents or mixtures of solvents and such a solution possesses the characteristics necessary for handling and application.

The principles of this invention may be applied in connection with a large varity of formulae. The relative amounts of cellulose nitrate, for example, and of its solvent, will obviously vary according to the consistency desired for every particular operation. One formula suitable for use in the production of the sand-paper of this invention, espe-' cially appropriate with relation to admixture with other material to be hereinafter referred to, is as follows: 16 ounces of cellulose nitrate (11 to 13% nitrogen) dissolved in one gallon of a solvent consisting of 60% amyl acetate, 10% acetone, 15% benzol and 15% denatured alcohol.

The cellulosic material of the foregoing solution is. the basis of the coating of the present invention and supplies the means by which the abrasive grains are retained on the base paper or backing material with suflicient tenacity to resist separation ofth'e abrasive grains from the backing when the sand-paper is used in association with water. In connection with the cellulosic solution I prefer to use one or more supplemental solutions, examples of which may be stated as follows:

I. of gum resins (25% copal--25% sandarac) 50% denatured alcohol.

II. 4 pints of rape seed oil, 5 pints of ethyl acetate.

When mixed in the proportion oftwogallons of the cellulosic solution, one gallon of solution I' and one gallon of solution II, a

composition will be formed which can be" applied with satisfactory results to the base material of the abrasive fabric. The result of using a solution such as No. I is not only .to actas a spreader or filter material with respect to the cellulosic material but to in- Application filed February 19, 1924. Serial 210.693,!)03.

sults.

EIASSUED crease the hardness and adhesiveness of the coating while the result of using solution No. II is to act as an emollient, i. e. to produce or to increase a condition of flexibility. Neither the resins of solution I nor the oil of solution II,.h0wever, are the active agents which retain the abrasive grains on the paper, that function being exercised by the cellulosic material of the cellulosic solution. The cellulose nitrate may be of any percent nitrogen composition and other solvents or combinations or proportions of solvents may be employed inplace of the specific solvents and proportions recited in the formula for. the cellulosic solution above given. A 7

result which is satisfactory for many purposes may also be obtained by using a composition of celluloid dissolved in a convenient solvent or mixture of solvents, celluloid being cellulose. nitrate treated with camphor, which is ordinarily termed a gum. Such a celluloid solution can be used either alone or in admixture with added camphor or camphor substitutes or gum resins may be added to increase or to accentuate hardness and adhesive qualities. Compounds of cellulose acetate may also be employed in place of cellulose nitrate with equally satisfactory re- The process of, manufacturing sand-paper in accordance with this invention consists of coating a fabric backing with the described composition, depositing abrasive grains upon this coating while in a plasic condition and dryingby evaporating the solvent. After the first coating which carries the abrasive grains has dried, the sand-paper is given. a top coating of the same composition and the paper is then thoroughly dried, which completes its manufacture. The coating of this of sand-paper in accordance with the new process can be handled wit-h the present equipment available at any sand-paper factory and 'does not require anyexcessive space for dry rooms, handling or other details of operation.

The use of the described top coating having the composition set forth, presents features of special utility. Such a top coating, so composed, or so constituted, has the eflect of more.or less completely filling in the spacesbetween the otherwise projecting tween the operator or the operating instruparts of the abrasive particles, thereby forming a matrix, as it were, through which the abrasive particles as they wear away, gradually penetrate more and more without at any time disturbing the matrix effect of said added film.

In mostindustries in which waterproof sand-paper is advantageously used, it is requisite that the rear surface of the fabric backing be also rendered waterproof. This waterproofing of the paper or fabric foundation material can be accomplished'by the use of any suitable waterproofing material either before or after the other side of the sheet is coated with abrasive. It is preferable, however, to coat the back of the fabric with the same composition which is used in waterproofing the face of the fabric. The application of a coat of this character to the back of the fabric results ina continuous film which obstructs access to the fibres of the fabric base. Thus no direct contact bementalities and the fabric of the base is permitted, and consequently there will be no frictional displacement of such fibres with respect. to each other. The use, therefore, of. this particular composition when used to coat the back of the fabric, presents special advantages.

Sand-paper produced in aecordance with this invent-ion is stable and does not deteriorate with the passage of time as is likely to occur in sand-paper in which the adhesive character of the coating is made to depend upon oxidation products of oil or varnish compositions.

I include within the scope of this invention sand-paper whether made with a backing of paper or any other conventional backing material of the sand-paper art as well a articles made from the sand-paper of my invention. I further include within the scope of this invention sand-paper whether coated on one or both sides of the fabric base or whether used in one or more coats on that side which bears the abrasive material.

What I claim is:

1. As a new article of manufacture, a sand paper product comprising a fabric base and abrasive material adhesively associated with one surface of said baseby waterproof coating material, the other surface of said base being covered with a cellulosic coating material. containing a filler and also an emollient to maintain flexibility in the filler and the associated cellulosic material, said coating constituting a protective film to prevent frictional displacement of the fibres constituting the fabric base in the use of the article.

2. An article of manufacture such as set forth in claim. 1 in which the abrasive material and the coating material by which it is adhesively associated with the base adhesively supports an added coating of waterproof cellulosic material containing a filler and also an emollient to maintain flexibility in the filler and the associated cellulosic material forming a film in the nature of a matrix for the abrasive particles through which the abrasive particles, as they wear away, gradually penetrate without disturbing the matrix effect of said added film.

In testimony whereof I have hereunto set my hand.

FRANK JOSEPH ORUPI. 

